In metropolitan areas, including Tokyo, air pollution is a serious issue. Among others, it is confirmed that particulate matters (PM) emitted from diesel vehicles are carcinogenic, and there are concerns about health hazards to residents.
In Tokyo, exhaust gases from diesel vehicles have been regulated since October 2003. Diesel vehicles subject to the regulation include large vehicles for business use such as buses and trucks. Those diesel vehicles that do not meet the PM emission standard stipulated by the Ordinance on Environmental Preservation are not allowed to drive in the Metropolitan area. Those automobiles that do not meet the standard must be replaced by those vehicles that meet the standard or must be equipped with the designated devices to reduce particulate matters (PM reducers).
To ensure the effectiveness of the regulation, TMG provides assistance to businesses to comply with the standard by assigning automobile pollution inspection officers, regulating those vehicles that do not meet the standard of the ordinance, creating a system to help businesses be furnished with loans to buy new vehicles to replace their vehicles that do not meet the standard, and creating a system to subsidize businesses to buy PM reducers.
As a result of such measures, the environment standard for suspended particulate matters (SPM) has been met since 2005 at all of the roadside air pollution monitoring stations.